Comparison of cranial versus medial minimally invasive plate osteosynthesis applications for the stabilization of simulated radius and ulna fractures in dog cadavers.

Background: Minimally invasive plate osteosynthesis (MIPO) is an emerging fracture management modality in small animal orthopedics. Although cranial plate application has been consistently advocated when performing radial MIPO, medial plating affords several purported advantages including improved screw purchase through the wider medial-to-lateral dimension of the radius, the potential to use smaller plates allowing more screws per unit length, and avoidance of extensor tendons which can complicate cranial plate placement in distal diaphyseal or metaphyseal fractures. Aim: To compare cranial versus medial MIPO applications for the stabilization of diaphyseal radius and ulna fractures in dog cadavers. Methods: Simulated bilateral antebrachial fractures were stabilized with cranial MIPO on one forelimb and medial MIPO on the contralateral limb, facilitated by a two-ring circular fixator construct. Procedure times and ease, number of fluoroscopic images obtained, and post-procedural frontal and sagittal alignment and radial length were compared between plating groups. The ease of construct placement, fracture reduction, radial approach, and plate application, were subjectively scored 1-5 for each procedure. Paired t-tests were performed to identify significant differences (p < 0.05) between the two plating groups. Results: There was no difference in total or incremental procedural times, subjective ease scores, or the number of fluoroscopic images obtained between plating groups. Both plating groups had comparable post-procedural frontal and sagittal plane alignment. There was a significant difference between plating groups for final radial length (p = 0.004) and change in radial length compared to the intact radii, (p = 0.002). Medial-plated radii measured longer than cranial-plated radii. Conclusion: The only outcome measure significantly different between plating groups was the post-procedural radial length. The change in length compared to intact radii was <1%, regardless of the plating group, and unlikely to be clinically relevant.

Osmotic pump maintains plasma concentrations of meloxicam for 6 days after orthopedic surgery in pigeons (Columba livia).

OBJECTIVE: To determine the plasma concentration of meloxicam delivered via an osmotic pump in pigeons undergoing orthopedic surgery and if an osmotic pump is a suitable alternative to repeated oral administration of this drug. ANIMALS: 16 free-ranging pigeons presented for rehabilitation with a wing fracture. PROCEDURES: An osmotic pump filled with 0.2 mL of 40 mg/mL meloxicam injectable solution was implanted subcutaneously in the inguinal fold of 9 pigeons under anesthesia for orthopedic surgery. The pumps were removed 7 days postsurgery. Blood samples were collected before pump implantation (time 0) and 3, 24, 72, and 168 hours after pump implantation in 2 pigeons in a pilot study then at 12, 24, 72, and 144 hours in the 7 pigeons of the main study. The blood of 7 other pigeons receiving meloxicam at 2 mg/kg, PO, every 12 hours was also sampled between 2 to 6 hours after the last meloxicam administration. Plasma meloxicam concentrations were measured via high-performance liquid chromatography. RESULTS: The plasma concentration of meloxicam was maintained at significant levels from 12 hours to 6 days after osmotic pump implantation. Median and minimum plasma concentrations in implanted pigeons were maintained at the same or higher level than those measured in pigeons that received meloxicam at a dose known to be analgesic in this species. No adverse effects attributable to either osmotic pump implantation and removal or meloxicam delivery were observed in this study. CLINICAL RELEVANCE: Plasma concentrations levels of meloxicam in pigeons implanted with osmotic pumps were maintained at a similar concentration or higher than the suggested analgesic meloxicam plasma concentration in this species. Thus, osmotic pumps could represent a suitable alternative to the frequent capture and handling of birds for analgesic drug administration.

Postoperative Severity Assessment in Sheep.

INTRODUCTION: Sheep are frequently used in translational surgical orthopedic studies. Naturally, a good pain management is mandatory for animal welfare, although it is also important with regard to data quality. However, methods for adequate severity assessment, especially considering pain, are rather rare regarding large animal models. Therefore, in the present study, accompanying a surgical pilot study, telemetry and the Sheep Grimace Scale (SGS) were used in addition to clinical scoring for severity assessment after surgical interventions in sheep. METHODS: Telemetric devices were implanted in a first surgery subcutaneously into four German black-headed mutton ewes (4-5 years, 77-115 kg). After 3-4 weeks of recovery, sheep underwent tendon ablation of the left M. infraspinatus. Clinical scoring and video recordings for SGS analysis were performed after both surgeries, and the heart rate (HR) and general activity were monitored by telemetry. RESULTS: Immediately after surgery, clinical score and HR were slightly increased, and activity was decreased in individual sheep after both surgeries. The SGS mildly elevated directly after transmitter implantation but increased to higher levels after tendon ablation immediately after surgery and on the following day. CONCLUSION: In summary, SGS- and telemetry-derived data were suitable to detect postoperative pain in sheep with the potential to improve individual pain recognition and postoperative management, which consequently contributes to refinement.

Approach and Interfragmentary Stabilization of Caudal Mandibular Fracture in the Cat.

An approach to caudal mandibular fracture stabilization is described along with three cases wherein the approach was applied in relatively young cats with traumatic mandibular fractures caudal to or involving the mandibular first molar. This approach was well-tolerated and facilitated a quick return to function as supported by minimal or no reliance on esophageal feeding tubes.

Evaluation of Surgical Gown Cuff Contamination During Orthopaedic Surgery in a Veterinary Teaching Hospital.

OBJECTIVE: The objective of this study was to determine the frequency of positive cultures of the surgical gown cuffs among scrubbed personnel prior to and immediately after orthopaedic surgical procedures performed on client-owned dogs. STUDY DESIGN: In this cross-sectional study, the left and right surgical gown cuffs of three scrubbed persons in 10 orthopaedic surgical procedures were individually sampled using a sterile wipe prior to and immediately after surgery in order to determine the frequency of and risk factors associated with positive bacterial cultures. RESULTS: Fifty of 120 (41.6%) cultures were positive with an even distribution before and after surgery. The three most common genera were Staphylococcus, Corynebacterium and Streptococcus. Using multivariable logistic regression models, humidity in the operating room (odds ratio: 1.04, 95% confidence interval: 1.00-1.08; p = 0.038) and the number of individuals scrubbed into surgery (odds ratio: 0.59, 95% confidence interval: 0.39-0.91; p = 0.016) had a significant effect on the likelihood of positive culture after surgery. Of the nine patients available for follow-up, one dog developed osteomyelitis. CONCLUSIONS: Maintaining the humidity in the operating room to the lowest comfortable level may reduce contamination of the surgical gown cuffs. Confirmation of bacterial contamination of surgical gown cuffs warrants adherence to operative guidelines to minimize the risk of surgical gown cuffs' contact with sterile attire, equipment and the surgical field during surgical procedures.

Epidural anesthesia in dogs undergoing hindlimb orthopedic surgery: effects of two injection sites.

This prospective clinical trial evaluated the effects of epidural anesthesia (EA) placed at the lumbosacral compared to the L5-L6 junction in dogs undergoing hindlimb orthopedic surgery. In all, 98 dogs were randomly assigned to receive injection at either L7-S1 (LS group) or L5-L6 (LL group) at the same local anesthetic regimen (1 mg/kg bupivacaine 0.5% and 0.1 mg/kg morphine 1%). Fentanyl (1 µg/kg) was the intraoperative rescue analgesia (iRA) administered if mean arterial pressure increased by 30% above pre-stimulation value. Procedural failure, iRA, hypotension, motor block resolution, and postoperative side effects were recorded. There were 7/47 (15%) epidural procedural failures in the LS group and 8/51 (16%) (P=1.00) in the LL group; iRA was administered in 21/40 (52%) LS group dogs and in 13/43 (30%) LL group dogs, respectively (P=0.047). The incidence of hypotension was 10/40 (25%) and 16/43 (37%) in the LS group and the LL group, respectively (P=0.25). Proprioceptive residual deficit at 8 hr after EA was recorded in 3/26 (12%) in group LS dogs and in 13/26 (50%) group LL dogs, respectively (P=0.01). The proprioceptive residual deficit at 24 hr in one dog (LL group) resolved within 36 hr. No episodes of postoperative urinary retention, pruritus or neurological damage were recorded. The L5-L6 EA decreased significantly iRA but delays the proprioceptive recovery time. Further studies are needed to determine whether a lower bupivacaine dose reduces the duration of the residual block retaining the same incidence of iRA.

Nonadherence to follow-up recommendations is common for dogs and cats undergoing orthopedic surgery.

OBJECTIVE: To evaluate owner adherence to recommendations for follow-up examination of dogs and cats following orthopedic procedures and identify factors associated with adherence versus nonadherence. SAMPLE: Medical records of 485 dogs and cats that underwent orthopedic surgery. PROCEDURES: Cases were categorized as urgent or elective. Information obtained from the medical records consisted of species, age, body weight, proximity to the hospital, procedure cost, recommendations for coaptation, use of financial aid, and number of owners. Cases were considered adherent to follow-up recommendations if, at the latest visit or communication, no further visits were recommended. Cases were considered nonadherent if owners did not return for recommended follow-up visits. RESULTS: Overall adherence to follow-up recommendations was 65.8% (319/485). Elective cases were 1.6 times as likely to be adherent to follow-up recommendations as were urgent cases, dog cases were 2.4 times as likely to be adherent as were cat cases, and cases with multiple owners listed were 2.1 times as likely to be adherent as were cases with 1 owner listed. Distance from the hospital had a statistically significant association with adherence, but the effect was not clinically important. Age, weight, coaptation, procedure cost, and use of financial aid were not significantly associated with adherence. CONCLUSIONS AND CLINICAL RELEVANCE: The percentage of dogs and cats lost to follow-up following orthopedic surgery at an academic veterinary teaching hospital was substantial (166/485 [34.2%]). Efforts to improve follow-up adherence are especially indicated for animals undergoing urgent procedures, animals with single owners, and cats.

Effect of knot location on the biomechanical strength and gapping characteristics of ex vivo canine gastrocnemius tenorrhaphy constructs.

OBJECTIVE: To evaluate the effect of knot location on the biomechanical strength and gapping characteristics of ex vivo canine gastrocnemius tenorrhaphy constructs. SAMPLE: 36 cadaveric gastrocnemius tendons from 18 adult dogs. PROCEDURES: Tendons were randomly assigned to 3 groups (12 tendons/group) and sharply transected and repaired by means of a core locking-loop suture with the knot at 1 of 3 locations (exposed on the external surface of the tendon, buried just underneath the external surface of the tendon, or buried internally between the apposed tendon ends). All repairs were performed with size-0 polypropylene suture. All constructs underwent a single load-to-failure test. Yield, failure, and peak forces, mode of failure, and forces required for 1- and 3-mm gap formation were compared among the 3 knot-location groups. RESULTS: Mean yield, failure, and peak forces and mean forces required for 1- and 3-mm gap formation did not differ significantly among the 3 groups. The mode of failure also did not differ significantly among the 3 groups, and the majority (33/36 [92%]) of constructs failed owing to the suture pulling through the tendinous substance. CONCLUSIONS AND CLINICAL RELEVANCE: Final knot location did not significantly affect the biomechanical strength and gapping characteristics of canine gastrocnemius tenorrhaphy constructs. Therefore, all 3 evaluated knot locations may be acceptable for tendon repair in dogs. In vivo studies are necessary to further elucidate the effect of knot location in suture patterns commonly used for tenorrhaphy on tendinous healing and collagenous remodeling at the repair site.

Transphyseal screw placement with and without hemicircumferential periosteal transection and elevation for correction of severe bilateral carpal varus deformities in an alpaca cria.

CASE DESCRIPTION: A 2.5-month-old 17.5-kg female alpaca cria was presented for evaluation and treatment of severe bilateral carpal varus deformities. CLINICAL FINDINGS: No lameness was evident at a walk, and neither carpal varus deformity could be corrected by means of manipulation. Radiography revealed severe varus of the left (27°) and right (21°) carpal regions. No additional conformational abnormalities were detected. TREATMENT AND OUTCOME: A single 2.7-mm transphyseal cortical screw was placed in the distolateral aspect of the radius in each limb. On reexamination 8 weeks after screw placement, the left carpal varus deformity had corrected from 27° to 2.6°, and the left transphyseal screw was removed. The right carpal varus deformity had improved but was still present (18°), and hemicircumferential periosteal transection and elevation was performed on the mediodistal aspect of the right radius. Five weeks after the second surgery, the right carpal varus deformity had corrected to 2.4°, and the right transphyseal screw was removed. Six months after the second screw removal, both thoracic limbs remained straight, the cria had a normal gait, and the owner was happy with the cosmetic result. CLINICAL RELEVANCE: Placement of a single transphyseal cortical screw with or without the addition of hemicircumferential periosteal transection and elevation can provide a favorable outcome in skeletally immature alpacas with severe carpal varus deformities.

Orthopedic Infections-Clinical Applications of Intravenous Regional Limb Perfusion in the Field.

For the equine veterinarian, orthopedic emergencies are a common occurrence in clinical practice, with traumatic wounds of the distal limb and penetrating injuries of the hoof being some of the most common medical conditions to affect horses. Intravenous regional limb perfusion is a technique widely used for the treatment of orthopedic infections in horses. The objectives of this review are to discuss some of the clinical applications for this treatment modality in the field and to review the technique for the practitioner.

Biomechanical effects of a titanium intervertebral cage as a stand-alone device, and in combination with locking plates in the canine caudal cervical spine.

OBJECTIVE: To evaluate the change in ex vivo biomechanical properties of the canine cervical spine, due to an intervertebral cage, both as a stand-alone device and in combination with plates. STUDY DESIGN: Experimental ex vivo study. ANIMALS: Cervical spinal segments (C5-C7) from eight canine cadavers. METHODS: The range of motion (ROM) and elastic zone stiffness (EZS) of the spines were determined with a four-point bending device in flexion/extension, lateral bending, and axial rotation for four conditions: native, discectomy, cage (at C6-C7), and cage with plates (at C6-C7). The disc height index (DHI) for each condition was determined using radiography. RESULTS: Discectomy resulted in overall increased ROM (p < .01) and EZS (p < .05) and decreased DHI (p < .005) when compared to the native condition. Placement of the cage increased DHI (p < .001) and restored total ROM during flexion/extension, lateral bending and axial rotation, and EZS during flexion/extension to the level of the native spine. Application of the plates further reduced the total ROM during flexion/extension (p < .001) and lateral bending (p < .001), but restored ROM in extension and EZS during lateral bending. No implant failure, subsidence, or significant cage migration occurred during loading. CONCLUSION: An anchorless intervertebral cage used as a stand-alone device was able to restore the disc height and spinal stability to the level of the native cervical spine, whereas the addition of plates further reduced the spinal unit mobility. CLINICAL SIGNIFICANCE: This study implies that the intervertebral cage may be used as a stand-alone device in the spinal unit fixation in the canine cervical spine.

An ex vivo biomechanical comparison of two suture materials and two pattern combinations for equine superficial digital flexor tendon tenorrhaphy.

OBJECTIVE: To compare biomechanical characteristics of three-loop pulley (3LP) pattern versus Bunnell technique (BT) using polydioxanone (PDS) suture; to determine the influence of polyester tape (PT) versus PDS on the BT for equine superficial digital flexor tendon (SDFT) tenorrhaphy; to compare BT with PT versus 3LP with PDS. STUDY DESIGN: Ex vivo biomechanical study. SAMPLE POPULATION: Forty equine forelimb SDFT. METHODS: Two experiments were performed: (1) 10 SDFT pairs were repaired with 3LP or BT using PDS; (2) 10 SDFT pairs were repaired with PDS or PT using BT. Load at failure, mode of failure, load at 2 mm gap, and gap at failure were obtained using a material testing machine. RESULTS: In experiment 1, 3LP + PDS1 had higher loads at failure (p < .001) and at 2 mm gap (p < .001), and smaller gap at failure than BT + PDS1 (p = .024). In experiment 2, BT + PT2 had higher loads at failure (p < .001) and at 2 mm gap (p = .001), and larger gap at failure (p = .004) than the BT + PDS2 . 3LP + PDS1 and BT + PT2 mostly failed by suture/implant pull-through while BT + PDS failed by suture breakage. BT + PT2 had greater load (p = .035) and gap at failure (p < .001) than 3LP + PDS1, with no difference in load at 2 mm gap (p = .14). CONCLUSION: The use of BT may be justified over 3LP if combined with PT. However, the larger size of the PT required stab incisions in the tendon for placement and was subjectively more difficult to place than PDS. CLINICAL SIGNIFICANCE: The BT + PT, although the strongest among the tested repairs, would only be able to withstand 12%-24% of the load encountered by the SDFT at walk.

Biomechanical analysis of accessory tendon graft augmentation for primary gastrocnemius tendon reconstruction in dogs.

OBJECTIVE: To evaluate the effect of accessory tendon graft (ATG) augmentation as an adjunct to a core locking-loop (LL) and epitendinous suture (ES) repair in a gastrocnemius tendon (GT) model. STUDY DESIGN: Randomized, ex vivo, biomechanical. POPULATION: Twenty-two canine GT musculotendinous constructs. METHODS: GT repair constructs were randomly divided into two groups (n = 10/group). After transection, paired GT were repaired with LL + ES alone or with concurrent ATG augmentation. Yield, peak and failure loads, tensile loads required to create 1 and 3 mm gapping, and failure modes were evaluated. Four GT were used as intact controls for validation of testing methodology. ATG constructs were compared to LL + ES and control specimens. RESULTS: Yield (p < .0001), peak (p = .0001) and failure loads (p = .0003) were greater when ATG was used for repair. Greater force was required to cause 1 mm (p = .0001) and 3 mm (p = .0002) gap formation in the ATG group, however, the frequency of gap formation did not differ between groups. All repaired constructs failed exclusively by suture pull-through. CONCLUSION: Autologous ATG augmentation as an adjunct to primary GT repair increased yield, peak and failure forces by approximately 1.6×, 1.9×, 1.8× respectively and required 2.1× greater force to cause 1 and 3 mm formation respectively compared to LL + ES repairs alone. CLINICAL SIGNIFICANCE: ATG augmentation should be considered as an autologous method to support and strengthen the primary GT repair. These results justify studies to determine the effect of ATG on clinical function following graft harvest in dogs.

Risk factors for surgical site infection associated with clean surgical procedures in dogs.

Surgical site infection (SSI) is associated with increased morbidity, cost and mortality in human medicine and with increased morbidity and cost in veterinary medicine. The aim of this study was to evaluate risk factors for SSI development after clean surgical procedures in dogs, treated at both first opinion clinics as well as referral hospitals. 1550 dogs scored 1 or 2 according to the American Society of Anesthesiologists (ASA), that underwent clean surgical procedures at 103 clinics located in Northern and Central Europe were included in the study. Data regarding the surgical procedure, surgery time use of perioperative antimicrobial prophylaxis (AMP), surgery type, intraoperative hypothermia, and the use of surgical implants were recorded according to predefined protocols. Active 30-day SSI surveillance was performed. A random effects logistic regression model was used to evaluate the association between the perioperative variables and SSI development. SSI was detected in 85/1550 dogs (5.5%); 25 occurred in the 500 orthopedic/neurosurgery procedures (5.0%), and 60 in the 1050 soft tissue procedures (5.7%). A total of 1524 dogs were included in the final multivariable model. Increased surgery time was the only variable associated with an increased risk of SSI. No association between the other risk factors evaluated in the study and SSI occurrence was detected. Efforts must therefore be made to keep the surgery time as short as possible. Orthopedic and neurosurgical procedures including those where an implant is placed should not automatically be regarded as high-risk procedures benefiting from perioperative AMP.

Complications and outcomes of cats with coxofemoral luxation treated with hip toggle stabilization using ultrahigh-molecular-weight-polyethylene or nylon (2009-2018): 48 cats.

OBJECTIVE: To report overall rate and type of complications and outcomes of cats with coxofemoral luxation managed with hip toggle stabilization (HTS), to compare rate of postoperative complications and outcomes of cats treated with ultrahigh-molecular-weight-polyethylene (UHMWPE) or nylon, and to identify risk factors for reluxation and non-excellent outcomes. STUDY DESIGN: Multi-institutional retrospective cohort study. SAMPLE POPULATION: Forty-eight client-owned cats. METHODS: Medical records of cats that underwent HTS from 2008-2018 using UHMWPE or nylon were reviewed. Univariable and multivariable logistic regression was performed to assess for factors associated with reluxation and non-excellent outcome. Final outcome was obtained from owner questionnaire. RESULTS: Intraoperative and postoperative complications were recorded in two (4.2%) and 11 (24.4%) cats, respectively. The most common postoperative complication was reluxation (n = 5 [11.1%]). Outcome was classified as excellent in 81.1% and good in 16.2% of cats after a median of 445.5 days (range, 53-3720). No difference in rate of complications or outcomes was identified between UHMWPE and nylon. Performance of additional orthopedic procedures, occurrence of intraoperative complications, and non-performance of capsulorrhaphy were associated with reluxation. Performance of additional non-hip procedures (orthopedic/nonorthopedic) was associated with non-excellent outcome. CONCLUSION: Hip toggle stabilization was associated with a low rate of intraoperative complications and reluxation and excellent long-term outcomes in most cats. No difference in rate of postoperative complications or outcomes of cats treated using UHMWPE or nylon was identified. Cats that underwent additional orthopedic procedures had greater risk of reluxation. CLINICAL SIGNIFICANCE: Hip toggle stabilization is an effective technique for management of coxofemoral luxation in cats. Comparable results are expected using UHMWPE or nylon.

Calcium sulfate antibiotic-impregnated bead implantation for deep surgical site infection associated with orthopedic surgery in small animals.

OBJECTIVE: To report the outcomes and complications associated with antibiotic-impregnated calcium sulfate beads for prevention and treatment of orthopedic-related surgical site infection (SSI) in companion animals. STUDY DESIGN: Retrospective case series. ANIMALS: Client-owned cats (n = 2) and dogs (n = 14). METHODS: Medical records of 16 cases in which implantation of antibiotic-impregnated calcium sulfate beads was performed for the prevention or treatment of SSI were reviewed. Information collected included signalment, prior surgery, reason for bead placement, antibiotics used, bacterial culture results, and clinical outcomes. RESULTS: Surgical site infection resolved in six of 10 animals treated therapeutically and did not occur in six of six animals treated prophylactically. Susceptibility of the causative bacteria to the antibiotic implanted was confirmed in five of six cases with resolved SSI treated therapeutically but in only one of four cases with unresolved SSI treated therapeutically. Complications directly related to bead placement were evident in only one case in which beads extruded from external skeletal fixator pin tracts 7 days after implantation. At final follow-up, 11 of 12 animals without SSI had satisfactory limb use and no clinical, cytologic, or radiographic evidence of infection. CONCLUSION: Implantation was well tolerated. Resolution of SSI was inconsistent; however, when bacteria were susceptible to the antibiotic implanted, SSI resolved in all but one case. CLINICAL SIGNIFICANCE: Antibiotic-impregnated calcium sulfate beads could be considered for prevention or treatment of orthopedic SSI in small animals. A prospective clinical study is required to obtain additional information, including the value of preoperative bacterial culture.

Use of Hausdorff Distance and Computer Modelling to Evaluate Virtual Surgical Plans with Three-Dimensional Printed Guides against Freehand Techniques for Navicular Bone Repair in Equine Orthopaedics.

OBJECTIVE: The aim of this study was to evaluate the surgical execution of a virtual surgical plan (VSP) with three-dimensional (3D) guides against a freehand approach in the equine navicular bone using an automated in silico computer analysis technique. STUDY DESIGN: Eight pairs of cadaveric forelimb specimens of adult horses were used in an ex vivo experimental study design with in silico modelling. Limbs received either a 3.5 mm cortical screw according to a VSP or using an aiming device. Using computed tomography and computer segmentation, a comparison was made between the executed screw and the planned screw using the Hausdorff distance (HD). RESULTS: Navicular bone mean HD registration error was -0.06 ± 0.29 mm. The VSP with 3D printing demonstrated significantly superior accuracy with a mean deviation of 1.19 ± 0.42 mm compared with aiming device group (3.53 ± 1.24 mm, p = 0.0018). The VSP group was 5.0 times more likely to result in a mean aberration of less than 1.0 mm (95% confidence interval, 0.62-33.4). A 3.5 mm screw with an optimal entry point can have a maximum deviation angle of 3.23 ± 0.07, 2.70 ± 0.06 and 2.37 ± 0.10 degrees in a proximal, dorsal and palmar direction respectively, prior to violating one of the cortical surfaces. CONCLUSION: Procedures performed using the 3D guides have a high degree of accuracy, with minimal mean deviations (<1 mm and <1 degree) of a VSP compared with those using the conventional aiming device. The use of VSP and the HD for evaluation of orthopaedic surgeries and outcome measures shows promise for simplifying and improving surgical accuracy.